Development and Application of Complete Equipment for High-speed Tunnel Boring and Bolting Machines

With the improvement of coal mining speed and mechanization level in China, traditional tunnel boring methods can no longer meet the actual needs. In order to solve the problems of low effciency, high labor intensity, slow tunnel boring speed, bad working environment and poor safety in traditional tunnel boring, on the basis of analyzing the development and application of coal roadway tunnel boring equipment at home and abroad, complete equipment for high-speed tunnel boring and bolting machines was developed by using the integrated technology of tunnel boring and bolting. The complete equipment for high-speed tunnel boring and bolting machines has the functions of tunnel boring and bolting synchronization, once-tunneling, negative pressure dust removal, digital guidance, independent cutting feed, digital cutting, safety monitoring and data interaction, which has the advantages of safety in use, reliability and effciency

An FPGA-based instrument for en-masse RRAM characterization with ns pulsing resolution

An FPGA-based instrument with capabilities of on-board oscilloscope and nanoscale pulsing (70 ns @ \pm 10 V) is presented, thus allowing exploration of the nano-scale switching of RRAM devices. The system possesses less than 1% read-out error for resistance range between 1 text{k}\Omega to 1 text{M}\Omega , and demonstrated its functionality on characterizing solid-state prototype RRAM devices on wafer; devices exhibiting gradual switching behavior under pulsing with duration spanning between 30 ns to 100 \µs. The data conversion error-induced degradation on read-out accuracy is studied extensively and verified by standard linear resistor measurements. The integrated oscilloscope capability extends the versatility of our instrument, rendering a powerful tool for processing development of emerging memory technologies but also for testing theoretical hypotheses arising in the new field of memristors

The Channel Switch Method of the Cambridge MK4 EIT System

With electrical impedance tomography (EIT) system’s development, more electrodes is required to get better detection performance. In this paper, we proposed a circuit design to switch channels to different electrodes quickly and stably

Properties and application of polyimide-based composites by blending surface functionalized boron nitride nanoplates

Properties and application of polyimide-based composites by blending surface functionalized boron nitride nanoplate

Effects of surface-functionalized aluminum nitride on thermal, electrical, and mechanical behaviors of polyarylene ether nitrile-based composites

Aluminum nitride (AlN) with high thermal conductivity was blended in polyarylene ether nitrile (PEN) to obtain a composite system. A ball milling process could provide AlN particles of smaller size with higher surface silylation for homogeneous particle distribution in polymeric matrix. Thermal, electrical, and mechanical behaviors of the produced composites were characterized to investigate the effects of particles on the performance of PEN-based composites with functionalized AlN. The composite exhibited thermal conductivity of 0.779 W m−1 K−1, a dielectric constant of 7.7, dielectric loss of 0.032, electrical resistivity of 1.39 GΩ.cm, and break strength of 36 N when the fraction of functionalized AlN increased to 42.3 vol%. A fitted equation based on the improved Russell's model could effectively predict a trend for thermal conductivity of the composite systems with consideration of interfacial resistance between AlN and surrounding PEN

A High speed, high bandwidth Versatile DAS for breast cancer detection

The data acquisition system (DAS) developed aims to get the 3D breast cancer tomography with 8 current injection channels and 117 voltage measurement channels, capable of generating and measuring voltages and currents. By adopting special electrode and careful circuit layout, the initial bandwidth without calibration can reach 5 MHz. Electrical test results show that the system has a SNR greater than 67dB at 5MHz without digital enhancement method

Quantitatively assessing ecological stress of urbanization on natural ecosystems by using a landscape-adjacency index

Urban spatial expansion poses a threat to regional ecosystems and biodiversity directly through altering the size, shape, and interconnectivity of natural landscapes. Monitoring urban spatial expansion using traditional area-based metrics from remote sensing provides a feasible way to quantify this regional ecological stress. However, variation in landscape-adjacency relationships (i.e., the adjacency between individual landscape classes) caused by urban expansion is often overlooked. In this study, a novel edge-based index (landscape-adjacency index, LAdI) was proposed based on the spatial-adjacency relationship between landscape patches to measure the regional ecological stress of urban expansion on natural landscapes. Taking the entire Yangtze River Delta Urban Agglomerations (YRD) as a study area, we applied the LAdI for individual landscape classes (Vi) and landscape level (LV) to quantitatively assess change over time in the ecological stress of YRD from 1990 to 2015 at two spatial scales: municipal scale and 5 km-grid scale. The results showed that the vulnerable zones (LV ≥ 0.6) were mainly distributed in the north of the YRD, and cultivated land was the most vulnerable natural landscape (Vi ≥ 0.6) at the 5 km-grid scale. The most vulnerable landscape at the municipal scale was cultivated land in 19 of 26 cities in each period, and that in the remaining 7 cities varied at distinct urbanization stages. We used scatter diagrams and Pearson correlation analysis to compare the edge-based LAdI with an area-based index (percent of built-up area, PB) and found that: LV and PB had a significant positive correlation at both the municipal scale and 5 km-grid scale. But there were multiple LVs with different values corresponding to one PB with the same value at the 5 km-grid scale. Both indexes could represent the degree of urban expansion; however, the edge-based metric better quantified ecological stress under different urban-sprawl patterns sharing the same percent of built-up area. As changes in land use affect both the size and edge effect among landscape patches, the area-based PB and the edge-based LAdI should be applied together when assessing the ecological stress caused by urbanization

A Dynamic and Complex Network Regulates the Heterosis of Yield-Correlated Traits in Rapeseed (Brassica napus L.)

Although much research has been conducted, the genetic architecture of heterosis remains ambiguous. To unravel the genetic architecture of heterosis, a reconstructed F2 population was produced by random intercross among 202 lines of a double haploid population in rapeseed (Brassica napus L.). Both populations were planted in three environments and 15 yield-correlated traits were measured, and only seed yield and eight yield-correlated traits showed significant mid-parent heterosis, with the mean ranging from 8.7% (branch number) to 31.4% (seed yield). Hundreds of QTL and epistatic interactions were identified for the 15 yield-correlated traits, involving numerous variable loci with moderate effect, genome-wide distribution and obvious hotspots. All kinds of mode-of-inheritance of QTL (additive, A; partial-dominant, PD; full-dominant, D; over-dominant, OD) and epistatic interactions (additive × additive, AA; additive × dominant/dominant × additive, AD/DA; dominant × dominant, DD) were observed and epistasis, especially AA epistasis, seemed to be the major genetic basis of heterosis in rapeseed. Consistent with the low correlation between marker heterozygosity and mid-parent heterosis/hybrid performance, a considerable proportion of dominant and DD epistatic effects were negative, indicating heterozygosity was not always advantageous for heterosis/hybrid performance. The implications of our results on evolution and crop breeding are discussed

Distributed state estimation for uncertain sensor networks with mixed time delays subject to sensor saturations

In this paper, the distributed state estimation problem is investigated for a class of uncertain sensor networks. The target plant is described by a set of uncertain difference equations with both discrete-time and infinite distributed delays, where two random variables are introduced to account for the randomly occurring nonlinearities. The sensor measurement outputs are subject to randomly occurring sensor saturations due to the physical limitations of the sensors. Through available output measurements from each individual sensor and its neighboring sensors, this paper aims to design distributed state estimators to approximate the states of the target plant in a distributed way. Sufficient conditions are presented which not only guarantee the estimation error systems to be globally asymptotically stable in the mean square sense but also ensure the existence of the desired estimator gains